Accumulator for strip-like material

ABSTRACT

The disclosure this thiy invention relates to an accumulator for strip-like material, such as steel sheet gauge stock issuing to a strip processing apparatus. The accumulator is shown located before a rolling mill and comprises two independent, but cooperative units, each including three stationary vertical spaced-apart rows of strip supporting rollers between which rows may be located two movable similar rows of strip supporting rollers; the rollers of the stationary rows varying in progressively increasing diameters from the side adjacent the movable rolls and the rollers of the movable rows having rollers complementary to the rollers to the stationary rows, but whose diameters vary progressively in a reverse order.

United States Patent [191 Shumaker 1 May 22, 1973 [75] Inventor: Charles Storer sburgh, Pa.

Shumaker, Pitt- [73] Assignee: United Engineering and Foundry Company, Pittsburgh, Pa.

221 Filed: Oct. 28, 1971 211 Appl.No.: 193,328

[30] Foreign Application Priority Data Dec. 30, 1970 Great Britain ..6l,703/70 [5 6] References Cited UNITED STATES PATENTS Butler et al. ..226/1 19 X 2,242,751 5/194] McFarland ..226/l89 Primary ExaminerAllen N. Knowles Attorney-Henry C. Westin [57] ABSTRACT The disclosure this thiy invention relates to an accumulator for strip-like material, such as steel sheet gauge stock issuing to a strip processing apparatus. The accumulator is shown located before a rolling mill and comprises two independent, but cooperative units, each including three stationary vertical spaced-apart rows of strip supporting rollers between which rows may be located two movable similar rows of strip supporting rollers; the rollers of the stationary rows varying in progressively increasing diameters from the side adjacent the movable rolls and the rollers of the movable rows having rollers complementary to the rollers to the stationary rows, but whose diameters vary progressively in a reverse order.

3 Claims, 2 Drawing Figures Patented May 22, 1973 2 Sheets-Sheet 2 ACCUMULATOR FOR STRIP-LIKE MATERIAL The present interest in the metal industry to operate rolling mills without interruption even though separate coils are being fed to the mill requires that the coils be joined together prior to being fed to the mill. In order to avoid a slowing down or stoppage of the mill to permit welding of the coils, a strip accumulator or looping device of some form must be provided of sufficient capacity to allow the strip to be continuously fed to the mill when the individual coils are being prepared.

As the space at the entry side of the mill is at a very high premium, past and present accumulators or looper arrangements have been objected to, among other reasons, because of the excessive amount of space they require. In a given mill arrangement, for example, the space allowed for the accumulator may exceed the space taken up by the mill itself, if not also the coil handling equipment associated therewith.

It is an object of the present invention, therefore, to provide a strip accumulator which will require very little space and one that can be arranged very compactly at the entry side of a processor and cooperate very conveniently with the normal coil handling equipment thereof.

More particularly, the present invention provides a strip accumulator comprising two spaced-apart rows of material supporting elements, each row comprising at least two of said elements arranged in parallel planes and one element of each row having a larger supporting area for the material than the other element thereof; the corresponding supporting elements of each of said two rows also being arranged in a common, but different plane than said parallel planes, means for supporting said two rows against movement in a direction of said parallel planes, a third row of material supporting elements having at least two material supporting elements arranged in a plane parallel to said parallel planes and between said first two rows, the supporting elements of the third row having supporting areas corresponding in size to a different one of the elements of said first two rows and arranged in a reverse order relative thereto with reference to the parallel planes, means for moving said third row in said parallel plane to a material feeding position where the material can be fed in a serpentine fashion over the supporting elements of the first two rows and under the elements of the third row and to a material accumulating position where the third row moves away from said first two rows to cause said support elements to form extended strains in the form of multiple loops of material.

lt is a further object of the present invention to provide two cooperative accumulator units wherein their movable carriages move in equal and opposite directions and are balanced to neutralize any loads being placed on the strip by the carriages and the weight of the strip itself and auxiliary torque generating means is provided to apply a selected constant tension on the strip.

These objects as well as other novel features and advantages of the present invention will be better appreciated when the following description thereof is read along with the accompanying drawings of which:

FlG. 1 is a diagrammatical elevational view of two cooperative accumulators built in accordance with the teaching of the present invention, and

FIG. 2 illustrates one of the accumulators shown in FIG. 1 in a strip-threading position.

Referring first to FIG. 1, there is illustrated the first stand 11 of a tandem cold rolling mill designed, for example, to reduce steel sheet gauge stock. As noted previously, it is intended that this mill is to be operated in a continuous manner, i.e., without interruption notwithstanding the fact that individual coils are to be fed to the mill. The individual coils are brought to the entry side of the mill and placed on pay-off reels 12 and 13 shown in block form in the FIG. 1. The pay-off reels, constructed in accordance with well-known designs, unwind the coils one at a time and issue the strip in a direction opposite to the direction that the strip passes to the mill 11. The ends of the succeeding coils unwound by the payoff reels 12 and 13 are brought to a welder 14, also shown in block form in FIG. 1 and similar to a well-known design, where the trailing end of the first coil is welded to the leading end of the second coil. After welding, the strip is fed to the first of two similar accumulators built in accordance with the present invention and which are arranged compactly ahead of the coil handling equipment and the adjacent mill stand 11.

The accumulators 15 and 16 are identical, except for the fact that the movable roll assemblies thereof move in an opposite direction for the reason to be more fully explained hereinafter. Because of the similarity between the accumulators 15 and 16, it is only deemed necessary to describe the components of one of them. In this regard reference will be made to the unit 15 which comprises a stationary frame 18 made up of three rows 19, 21 and 22 of strip supporting rolls which are rotatably supported in the frame 18. The rolls in each of the three rows are spaced apart and each row is made up of four pairs of rolls. The uppermost rolls 23 of each row are of larger diameters than the diameters of the other three in which the diameters of the other three are progressively smaller moving away from the rolls 23 so that the lowest roll 24 of each row row is considerably smaller than the upper roll thereof. Attention is directed to the spacing between the corresponding rolls of each row and with reference to the largest diameter rolls 23 it will be noted that the separations are slightly larger than the diameters of the lowermost rolls 24. The reason for this, as will be more clearly seen later on, is to allow for the positioning of rolls having diameters equal to that of the small rolls 24 between the spacing formed by the two adjacent larger rolls 23.

FIG. 1 illustrates the accumulators in their operative positions, as distinguished from their feeding positions, so that the rolls of the rows 19, 21 and 22, which are sometimes referred to as stationary rolls, are disposed away from a series of other rolls which are the movable rolls of the accumulators. As shown in FIG. 1, and in still referring to the accumulators 15, the movable rolls are supported in a carriage 25 and consist of two rows 26 and 27 of rolls provided in the space between the rows 19, 21 and 22, and having not only a like number of rolls, but rolls of diameters equal to the rolls of the rows 19, 21 and 22. However, in the movable carriage the larger rolls 28 of the rows 26 and 27 are in reverse order looking at the accumulator in the vertical plane and in this way the space provided between the adjacent rolls in the horizontal direction of the stationary rows 19, 21 and 22 are correlated with the diameters of the rolls of the movable carriage 25 so that when the carriage is moved into its feeding position the smaller rolls 29 of the movable carriage 25 may pass between the largest rolls 23 of the stationary frame 18, as do the corresponding intermediate rolls thereof with reference to the intermediate rolls of the movable carriage and, finally, the larger rolls 28 of the movable carriage pass between the smaller rolls 24 of the stationary frame.

It is important to note at this point that the selection of the diameters of the varying diameter rolls of the rows 19, 21 and 22 and 26 and 27 is such that the decrease in diameter of the rolls provides sufficient space between the loops formed by the respective rolls so as to avoid scratching of the strip as it passes through the accumulator.

As already noted, the accumulator 16 is identical to the accumulator 15, except for the fact that the movable carriage 31 of the accumulator 16 moves relative to assuming its feeding position to a direction opposite to the movement of the carriage 25 of the accumulator 15. The strip is fed to the accumulator 15 first over guide roll 30 and above the rolls of the rows 19, 21 and 22 of the stationary frame 18. It leaves the accumulator 15 by passing over the innermost smallest diameter roll 24 which passage is shown in FIG. 1, where the strip is then conveyed to the innermost large diameter roll 23 of the stationary frame 32 of the accumulator 16. The strip leaves the accumulator 16 by being wound around the innermost small diameter roll 24 of the stationary will always accommodate the same amount of strip and be subject to an equal amount of outside tension from the torque motor 44.

As above described, the accumulators 15 and 16 provide a very large strip storage capacity within a minimum of space. As illustrated in FIG. 1 by the arrowed lines which depict the course of the strip during the opframe 32 of the accumulator 16 where it is led to a deflector roll 33 and, hence, to a tension bridle 34 from where it then enters the mill 11.

It is a feature of the invention when it is desirable to employ two cooperative accumulator units similar to units 15 and 16 that in a very simple and economical way the strip be subject to a balancing of strip loads and a control of the tension of the strip. This is achieved, in part, by arranging the movable carriages 25 and 31 of the accumulators l5 and 16, respectively, to counter balance the load or weight of the strip itself and the weight of each carrier which would otherwise be placed on the strip. FIG. 1 shows associated with the movable carriage 25 an attached chain 35 which by a guide roll 36 is led to the movable carriage 31 of the accumulator 16 over a guide roll 37, where the chain is attached to the movable carriage 31. Similarly, the opposite portions of the frames of the movable carriages 25 and 31 are attached to a chain. In this case there is provided a chain 38 attached to the lower portion of the frame of the movable carriage 25 of the accumulator 15 which is guided by a guide roll 41 to a sprocket 42. This sprocket 42 is driven by a gear reducer 43 which, in turn, is connected to an electrical torque motor 44 so as to provide a constant driving torque to the sprocket 42. Associated with the torque motor in a customary manner is anoverspeed limit switch 45 and a brake assembly 46. The chain 38 is guided around the sprocket 42 by two guide rolls 47 from where the chain is guided to the accumulator 16 over a guide roll 48 after which it is secured to the lower portion of the frame of the movable carriage 31 of the accumulator 16. Since the strip weight and the weight of the carriers of each accumulator are neutralized, the torque motor can be sized for only the actual range of tension desired to be placed on the strip.

It will be seen from this description that the counterbalance chain torque motor arrangement will assure the equal displacement of the movable carriages, howbeit in opposite directions so that each accumulator erating phase of the accumulators, each accumulator is adapted to form a total of sixteen separate strands, not counting the two exit strands thereof, and which, while passing very close to each other, are prevented from contacting, as noted before, by the differences in diameters of support rolls. Thus, the two accumulators form a total of thirty-two strands which, when the movable carriages 25 and 31 are in their maximum extended position provide a storage capacity of 3,000 feet based on a carriage movement of 94 feet. In relating this capacity to the rolling of sheet gauges, the following data becomes relevant. The gauge of the strip being stored will fall between 0.060 to 0.150 inches, the 0.090 inch stock making up a large portion of the material stored. Based on a thickness of 0.060 inch, the weight of the strip will be 10.5 lbs./ft. at 50 inches wide; at 0.150 inches and at 72 inches wide, the weight will come to 37 lbs./ft. The tension exerted on the strip by the torque motor 44 will range from 50 lbs./in. width. The mill will have an entry rolling speed of 500 to 2,000 ft./min. and a delivery speed of 1,000 to 5,000 ft./min.

Starting at the point where both accumulators have been filled to their total capacity, for a mill entry speed of 1,000 f.p.m. and a coil having a length of 4,000 feet, the input speed of the strip going to the first accumulator can be as high as 4,000 f.p.m. until the total capacities of the accumulators are reached after which the speed can be reduced to equal the mill entry speed. Of course, the output speed of the second accumulator 16 will be the same as the mill entry speed, namely, 1,000 f.p.m. The entry speed range of the first accumulator is based on a coil preparation time, including welding, of approximately 1 minutes.

One of the features of the accumulators of the present invention is to provide a quick and convenient way for initially feeding the accumulators when the first set of coils are to be unwound. FIG. 2 is designed to show the feeding position of the rolls of the accumulator 15. In this regard it will be noted that the carriage 25 has been raised so that its small diameter rolls 29 of the rows 26 and 27 are placed above the stationary large diameter rollers 23 of the rows 19, 21 and 22. This movement can be brought about by operation of the motor 44. The same condition exists with reference to the next adjacent rolls of the movable carriage 25 with respect to the next largest rolls of the stationary rows until it will be noted that the largest rollers 28 of the movable carriage are positioned above the smallest rollers 24 of the stationary carriage. In this position it is only necessary to feed the strip between the four pairs of horizontal rows of rolls above identified after which the movable carriage 25 is free to be lowered to form the multiple strands as depicted in FIG. 1.

The feeding of the accumulator 16 is done in a similar manner; it being appreciated that the carriage 25 of the accumulator 15 is not moved until the strip has been fed through both accumulators and actually passed to the tension bridle 34.

In accordance with the provisions of the patent statutes, l have explained the principle and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof.

1 claim:

1. In an accumulator for strip-like material comprising two separate units:

each having two spaced-apart rows of material supporting elements,

each row comprising at least two of said elements arranged in a common first plane in which one of said two elements has a larger supporting area for the material than the other,

said two elements of one row having a corresponding relationship with the said two elements of the other row, in which the corresponding elements are arranged in common planes, means for supporting said rows against movement in a direction of said first plane,

a third row of material supporting elements having at least two material supporting elements arranged in a plane parallel to said first plane and between said first two rows,

each of the supporting elements of said third row having supporting areas corresponding in size to a different one of the corresponding elements of said first two rows and arranged in a reverse order with reference to the arrangement of the elements of said first two rows in said first plane,

means for moving said third row in said parallel plane between a material feeding position where the material is fed in serpentine fashion over the elements of the first and second rows and under the elements of the third row and a material accumulating position where the third row moves away from said first two rows to cause said support elements to form multiple extended strands of continuous loops of said material,

said units being spaced apart relative to the incoming feeding direction of the material and wherein said movable row of one unit, during accumulation, moves in a direction opposite to the movable row of the other units with reference to said first plane, and

wherein the movable elements of said two units are arranged to move in parallel, but opposite directions thereby serving to counterbalance the weight of the materials supported by the respective units to equalize the tension in the materials thereof.

2. In an accumulator according to claim 1 including means for equalizing the displacement of said opposed movable rollers of each unit.

3. In an accumulator according to claim 2 wherein said equalization is accomplished at least in part by a torque motor means and means for connecting said motor means to the movable rows of said two units. 

1. In an accumulator for strip-like material comprising two separate units: each having two spaced-apart rows of material supporting elements, each row comprising at least two of said elements arranged in a common first plane in which one of said two elements has a larger supporting area for the material than the other, said two elements of one row having a corresponding relationship with the said two elements of the other row, in which the corresponding elements are arranged in common planes, means for supporting said rows against movement in a direction of said first plane, a third row of material supporting elements having at least two material supporting elements arranged in a plane parallel to said first plane and between said first two rows, each of the supporting elements of said third row having supporting areas corresponding in size to a different one of the corresponding elements of said first two rows and arranged in a reverse order with reference to the arrangement of the elements of said first two rows in said first plane, means for moving said third row in said parallel plane between a material feeding position where the material is fed in serpentine fashion over the elements of the first and second rows and under the elements of the third row and a material accumulating position where the third row moves away from said first two rows to cause said support elements to form multiple extended strands of continuous loops of said material, said units being spaced apart relative to the incoming feeding direction of the material and wherein said movable row of one unit, during accumulation, moves in a direction opposite to the movable row of the other units with reference to said first plane, and wherein the movable elements of said two units are arranged to move in parallel, but opposite directions thereby serving to counterbalance the weight of the materials supported by the respective units to equalize the tension in the materials thereof.
 2. In an accumulator according to claim 1 including means for equalizing the displacement of said opposed movable rollers of each unit.
 3. In an accumulator according to claim 2 wherein said equalization is accomplished at least in part by a torque motor means and means for connecting said motor means to the movable rows of said two units. 